Analysis On Valence Electronic Structures Of Al-Li-Cu Alloy And Its Effects On Properties Of Strengthening

The valence electron structures of maid phases and phase interphase boundaries in Al-Li-Cu based alloy were analyzed according to the Empirical Electronic Theory in solid and molecules (EET). The following aspects are included in this thesis:1. The models of valence electron structure of maid phases in Al-Li-Cu based alloy were established. The solid solution of Al-Li-Cu based alloy was contained four cells: a-Al cell, Al-Li cell, Al-Cu cell and Al-Li-Cu cell. The valence electron structures of above cells were calculated.2. The valence electron structures of the precipitations of Al-Li-Cu based alloy in early aging, such as d (Al3Li),0",0'(Al2Cu), 0(Al2Cu) and Ti(Al2CuLi), were calculated.3. The valence electron structures of phase interphase boundaries between the matrix and the cells above, the matrix and the precipitations were calculated.The results show that:The strong interaction of Al with Li and Cu in solid solution of Al-Li-Cu based alloy, which lead to the behavior of Al-Li segregation, Al-Cu segregation and Al-Li-Cu segregation. The strong segregations are restrained the growth of the matrix, and the strengthening of the alloy was promoted.On the interphase boundaries between the matrix and the precipitates, electronic density is continued in Al-Li-Cu based alloy. The functions of aging hardening and precipitation hardening are remarkable in the alloy.